The overall objective of this proposal is to study the role glycerol plays in the control of food intake and body weight. Previous work has shown that when glycerol is infused continuously at a slow rate into the third ventricle of the brain of rats, they display a temporary hypophagia and lose body weight until it reaches a new lower level. The current proposal will attempt to determine the extent to which insulin is involved in glycerol effect. Various doses of insulin will be infused continuously into the third ventricle of the brain of rats and its effect on food intake and body weight will be determined. If the results of this study warrant it, combinations of insulin and glycerol will then be infused continuously into the third ventricle to determine whether or not there is a synergism between glycerol and insulin on food intake and body weight. In addition, a number of studies will be carried out to determine the effects on food intake of drugs which are known to alter the concentration of plasma glycerol levels. These studies will be carried out to determine if manipulation of endogenous plasma glycerol concentrations has the same effects on food intake as does exogenous administration of glycerol.